Vibration Damping Tool for Downhole Electronics

ABSTRACT

A shock reduction tool includes an upper interconnect module configured to electrically and mechanically orient and connect to an upper module and a lower interconnect module configured to electrically and mechanically orient and connect to a lower module. A shock absorber section is disposed between the upper interconnect module and the lower interconnect module. A wire management section is disposed between the upper interconnect module and the lower interconnect module. A plurality of wires electrically connect the upper interconnect module and the lower interconnect module and pass through the shock absorber section and the wire management section.

BACKGROUND

Downhole tools are subjected to substantial forces and vibration duringdrilling. Sensor packages and other sensitive downhole electronics, suchas those housed in measurement-while-drilling (MWD) tools, steeringtools, gyros, or logging-while-drilling (LWD) tools, are particularlyvulnerable to damage from vibration and shock during drilling.Electronics in downhole tools are often mounted in ways that reduce thevibration and shock that is felt by the electronics, but ultimately thevibration and shock still reduce the life cycle of the electronics andadd fatigue and wear to the bottom hole assembly. Reducing shock andvibration felt by the electronics extends their life cycle, which savesvaluable time and money that would be spent replacing or repairing thedirectional sensors and electronics. Accordingly, additional measures tominimize shock and vibration that reaches electronics are valuable.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of the embodiments, reference will nowbe made to the following accompanying drawings:

FIG. 1 is a schematic representation of a drilling system including adownhole tool with a shock reduction tool according to the principlesdisclosed herein;

FIG. 2 schematically illustrates a MWD tool including a shock reductiontool according to the principles disclosed herein;

FIGS. 3A-3F are cross-sectional views of a shock reduction toolaccording to the principles disclosed herein;

FIG. 4 is a wire management section of a shock reduction tool accordingto the principles disclosed herein.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

The present disclosure relates to a shock and vibration reduction tool(hereinafter “shock reduction tool”) for downhole tools with electronicor sensitive mechanical components. The drawings and the descriptionbelow disclose specific embodiments with the understanding that theembodiments are to be considered an exemplification of the principles ofthe invention, and are not intended to limit the invention to thatillustrated and described. Further, it is to be fully recognized thatthe different teachings of the embodiments discussed below may beemployed separately or in any suitable combination to produce desiredresults. The term “couple,” “couples,” or “coupled” as used herein isintended to mean either an indirect or a direct connection. Thus, if afirst device couples to a second device, that connection may be througha direct connection; e.g., by conduction through one or more devices, orthrough an indirect connection; e.g., by convection or radiation.“Upper” or “uphole” means towards the surface (i.e. shallower) in awellbore, while “lower” or “downhole” means away from the surface (i.e.deeper) in the wellbore.

Referring now to FIG. 1, a drill string 10 is suspended in a wellbore 12and supported at the surface 14 by a drilling rig 16. The drill string10 includes a drill pipe 18 coupled to a downhole tool assembly 20. Thedownhole tool assembly 20 includes multiple (e.g., twenty) drill collars22, a measurement-while-drilling (MWD) tool assembly 1, a mud motor 24,and a drill bit 26. The drill collars 22 are connected to the drillstring 10 on the uphole end of the drill collars 22, and the uphole endof the MWD tool assembly 1 is connected to the downhole end of the drillcollars 22, or vice versa. The uphole end of the mud motor 24 isconnected to the downhole end of MWD tool assembly 1. The downhole endof the mud motor 24 is connected to drill bit 26.

The drill bit 26 is rotated by rotary equipment on the drilling rig 16and/or the mud motor 24 which responds to the flow of drilling fluid, ormud, which is pumped from a mud tank 28 through a central passageway ofthe drill pipe 18, drill collars 22, MWD tool assembly 1 and then to themud motor 24. The pumped drilling fluid jets out of the drill bit 26 andflows back to the surface through an annular region, or annulus, betweenthe drill string 10 and the wellbore 12. The drilling fluid carriesdebris away from the drill bit 26 as the drilling fluid flows back tothe surface. Shakers and other filters remove the debris from thedrilling fluid before the drilling fluid is recirculated downhole.

The drill collars 22 provide a means to set weight off on the drill bit26, enabling the drill bit 26 to crush and cut the formations as the mudmotor 24 rotates the drill bit 26. As drilling progresses, there is aneed to monitor various downhole conditions. To accomplish this, the MWDtool assembly 1 measures and stores downhole parameters and formationcharacteristics for transmission to the surface using the circulatingcolumn of drilling fluid. The downhole information is transmitted to thesurface via encoded pressure pulses in the circulating column ofdrilling fluid.

FIG. 2 schematically illustrates the inside of MWD tool assembly 1, inaccordance with one embodiment. The MWD tool assembly 1 includes acollar 201 that includes a seat 230 in which an orienting sub 230 of anMWD tool 200 is disposed. Collar 201 is typically non-magnetic in orderto allow measurements of the outside formation conditions to be taken bythe MWD tool 200 from within the collar 201. In the prior art, MWD toolsoften include multiple discrete modules that are electronicallyconnected to form the MWD tool 200. The multiple discrete modules areoften connected using an interconnect module that provides electricalconnectors and, optionally, a centralizer for centralizing the MWD tool200 within the collar 201. Embodiments of the present disclosure place ashock reduction tool 210 between at least two modules: lower module 202and upper module 220. Lower module 202 may include, for example, apulser that produces pressure signals to transmit measurement data tothe surface. Upper module 220 may include, for example, various sensors,such as directional sensors, microprocessors, and other electroniccircuitry. Embodiments of the present disclosure are not limited to anyparticular combination of electronic modules for steering tools, MWDsystems, LWD systems, or other downhole electronic systems.

Embodiments of the present disclosure provide a shock reduction toolthat provides an electrical connection between at least two modules of adownhole tool, such as an MWD or LWD system. A cross-section of a shockreduction tool in accordance with one embodiment is shown in FIGS.3A-3F, with FIG. 3A at the upper end of the shock reduction tool andFIG. 3F at the lower end of the shock reduction tool in this embodiment.FIG. 3A is an end view of a male or female electrical connector 303 thatconnects to upper module 220. FIG. 3F is an end view of a male or femaleelectrical connector 304 that connects to lower module 202. Theelectrical connectors 303, 304 may be any electrical connectors adaptedfor use with the modules 202, 220. Common electrical connectors betweenMWD and LWD modules include MDM connectors.

FIG. 3B includes an upper interconnect module 301, which provides asealed mechanical connection to the upper module 220. Similarly, FIG. 3Eincludes a lower interconnect module 302, which provides a sealedmechanical connection to the lower module 202. The interconnect modules301, 302 are selected according to the specifications of the modules202, 220. The interconnect modules 301, 302 are configured to be similarto commercially available interconnect modules. The electrical andmechanical components used for the commercially available interconnectmodules are also commercially available.

From interconnect module 301, wires 340 extend downward from electricalconnector 303 into an interconnect crossover 343. The wires 340 mayterminate in a connector 341 with pins that pass through a pressurebulkhead feedthru 342. The interconnect crossover 343 provides themechanical connection between a body 350 of the shock reduction tool andthe interconnect module 301. In FIG. 3C, wires 351 extend through thebody 350 and through shock absorber section 330. Embodiments of thepresent disclosure are not limited to any particular design for theshock absorber section 330. One example of a shock absorber that may beadapted for use with embodiments of the present disclosure is theELIMINATOR HYDRAULIC SHOCK TOOL available from THRU TUBING RENTAL(“TTR”) (Houston, Tex.). Any shock absorber design may be adapted foruse with embodiments of the present disclosure so long as it contains apassage for wires 351 or other electrical conduit to pass through.

The axial distance between electrical connectors varies with the axialextension and compression of the shock absorber section 330 as itabsorbs and dampens shock and vibration during the drilling process. Asa result, the wires extending through the shock reduction tool must havelength to extend at least the maximum length possible from extension ofthe shock absorber section 330. Holding the wires in tension may lead tofailure of the wires. Having extra slack in the wiring can lead toabrasion damage of the wires as the slack comes and goes with thechanging axial length.

With these issues in mind, the shock reduction tool includes a wiremanagement section 360, an embodiment of which is shown in FIG. 3D. Inthis embodiment, the wires 351 are contained in multiple sections oftubing 361. The sections of tubing 361 may be formed from, for example,stainless steel. The sections of tubing 361 are helically wound insideof the wire management section 360. Each section have tubing 361 mayhave multiple wires 351. In one embodiment, there are four sections oftubing 361, each with two wires 351 inside. The helically wound sectionsof tubing 361 may be nested within each other. The inside of the wiremanagement section 360 may be pressure balanced and filled withdielectric fluid, such as oil, to lubricate and dampen the movement ofthe sections of tubing 361 as the helically wound portions extend andcompress with the axial movement of the shock absorber section 330.

The inside of the wire management section 360 may be at the ambientdownhole pressure. The tubing 361 may be sealed within the wiremanagement section 360 during assembly, which results in the inside ofthe tubing 361 having a lower pressure than the ambient downholepressure. If sealed without any pressure compensation, the strength oftubing 361 is selected to withstand the crushing forces resulting fromthe pressure differential between the inside of tubing 361 and ambientdownhole pressure.

On the lower end of the wire management section 360, the wires 351continue inside the tubing 361 to interconnect crossover 343. The wires351 continue to connector 341 and pass through pressure bulkheadfeedthru 342 to connect with the wiring inside interconnect module 302.

Although the embodiment in FIGS. 3A-3F is described in one orientationwith FIG. 3A on the upper end and FIG. 3F on the lower end, those havingordinary skill in the art will appreciate that the shock reduction toolmay be oriented in the opposite direction with the electrical connectorends reversed or with the wire management section 360 above the shockabsorber section 330. Further, more than one shock absorber section 330may be included in the shock reduction tool, and the wire managementsection 360 may be disposed in between those two or more shock absorbersections 330.

In FIG. 4, a wire management section 401 in accordance with anotherembodiment is shown. Instead of tubing, the wire management section 401routes wires 402 through a flexible hydraulic hose 403, which may bearmored. Each of the wires 402 may route through the single flexiblehydraulic hose 403, or divided between multiple hydraulic hoses 403. Theflexible hydraulic hose 403 may terminate at opposing ends with ANfittings 405, for example, to connect to other sections of the shockreduction tool.

Inside the wire management section 401, the flexible hydraulic hose 403is arranged into a loose knot 410, which is a square knot in theembodiment shown in FIG. 4. As the ends of the hydraulic hose are pushedtowards each other and pulled from each other with the travel of theshock absorber section, the loose knot 410 loosens and tightens withinthe constraints of the wire management section 401. The loosening andtightening of the loose knot 410 provides sufficient travel for thewires 402 contained therein to avoid excessive tension on the wires 402.Those having ordinary skill in the art will appreciate that other knotconfigurations may be used, or, alternatively, the hydraulic hose 403may be arranged in a loop without being knotted. In one embodiment, atleast a portion of the flexible hydraulic hose 403 may be coated orwrapped with a low friction and/or abrasion resistance coating, such asa shrink wrap Teflon® tube. The reduced friction allows for the looseknot 410 to loosen and tighten more freely within the wire managementsection 401 to avoid damage to the wires 402 contained therein.

The inside of wire management section 401 may be filled with fluid, suchas oil, and exposed to ambient downhole pressure. The flexible hydraulichose 403 may be fluidicly coupled to a pressure compensation chamberthat allows for the inside of the flexible hydraulic hose 403 to balancewith the ambient downhole pressure. At least some form of pressurecompensation may be desirable because flexible hydraulic hose 403generally has low resistance to collapse pressure. Pressure balancingreduces the pressure differential to a level that does not collapse theflexible hydraulic hose 403.

The embodiments disclosed herein allow for multiple modules containingelectronics to be electrically connected through a shock reduction tooldisposed between at least two modules. The shock reduction tool reducesthe shock and vibration experienced by the electronics in the moduleswhile allowing for the modules to be electrically connected using commonelectrical connectors. The reduction in shock and vibration can increasethe life expectancy of the modules relative to what their lifeexpectancy would be if directly interconnected as in the prior art MWDs,LWDs, and other downhole electrical systems.

While specific embodiments have been shown and described, modificationscan be made by one skilled in the art without departing from the spiritor teaching of this invention. The embodiments as described areexemplary only and are not limiting. Many variations and modificationsare possible and are within the scope of the invention. Accordingly, thescope of protection is not limited to the embodiments described, but isonly limited by the claims that follow, the scope of which shall includeall equivalents of the subject matter of the claims.

What is claimed is:
 1. A shock reduction tool, comprising: an upperinterconnect module configured to electrically and mechanically orientand connect to an upper module; a lower interconnect module configuredto electrically and mechanically orient and connect to a lower module; ashock absorber section disposed between the upper interconnect moduleand the lower interconnect module; a wire management section disposedbetween the upper interconnect module and the lower interconnect module;and a plurality of wires electrically connecting the upper interconnectmodule and the lower interconnect module and passing through the shockabsorber section and the wire management section.
 2. The shock reductiontool of claim 1, wherein the wire management section is filled withfluid and exposed to ambient wellbore pressure.
 3. The shock reductiontool of claim 2, wherein the plurality of wires are disposed in at leastone section of tubing in the wire management section.
 4. The shockreduction tool of claim 3, wherein the at least one section of tubingcomprises a helically wound portion inside the wire management section.5. The shock reduction tool of claim 4, wherein the plurality of wiresare divided between a plurality of sections of tubing in the wiremanagement section.
 6. The shock reduction tool of claim 5, wherein thehelically wound portions of the plurality of sections of tubing are in anested arrangement.
 7. The shock reduction tool of claim 2, wherein theplurality of wires are disposed in a flexible hydraulic hose inside thewire management section.
 8. The shock reduction tool of claim 7, whereinthe flexible hydraulic hose is tied into at least one knot inside thewire management section, and wherein the at least one knot is configuredto loosen and tighten in response to axial movement of the shockabsorber section.
 9. The shock reduction tool of claim 8, wherein theinside of the flexible hydraulic hose is pressure compensated.
 10. Ameasurement-while-drilling tool, comprising: an upper electronics modulecomprising at least one sensor; a lower electronics module; a shockreduction tool disposed between and configured to mechanically andelectrically connect the upper electronics module and the lowerelectronics module, wherein the shock reduction tool comprises a shockabsorber section and a wire management section.
 11. Themeasurement-while-drilling tool of claim 10, wherein the wire managementsection is filled with fluid and exposed to ambient wellbore pressure.12. The measurement-while-drilling tool of claim 11, wherein theplurality of wires are disposed in at least one section of tubing in thewire management section.
 13. The measurement-while-drilling tool ofclaim 12, wherein the at least one section of tubing comprises ahelically wound portion inside the wire management section.
 14. Themeasurement-while-drilling tool of claim 13, wherein the plurality ofwires are divided between a plurality of sections of tubing in the wiremanagement section.
 15. The measurement-while-drilling tool of claim 14,wherein the helically wound portions of the plurality of sections oftubing are in a nested arrangement.
 16. The measurement-while-drillingtool of claim 11, wherein the plurality of wires are disposed in aflexible hydraulic hose inside the wire management section.
 17. Themeasurement-while-drilling tool of claim 16, wherein the flexiblehydraulic hose is tied into at least one knot inside the wire managementsection, and wherein the at least one knot is configured to loosen andtighten in response to axial movement of the shock absorber section. 18.The measurement-while-drilling tool of claim 17, wherein the inside ofthe flexible hydraulic hose is pressure compensated.